Method of manufacturing battery plate grids



June 23, 1970 3,516,275

METHOD OF MANUFACTURING BATTERY PLATE GRIDS D. H. MORRELL ET AL v Filfid. Feb 2., 1968 Q a. Jtml/ Tim- BW.M

ATTORNEYS United States Patent 3,516,275 METHOD OF MANUFACTURING BATTERY PLATE GRIDS Donald H. Morrell, Sutton Coldfield, and Alan Williams,

Solihull, England, assignors to Joseph Lucas (Industries) Limited, Birmingham, England, a British company Filed Feb. 2, 1968, Ser. No. 702,670 Claims priority, application Great Britain, May 18, 1967, 23,161/ 67 Int. Cl. B21h 8/00 U.S. Cl. 72-198 3 Claims ABSTRACT OF THE DISCLOSURE A method of manufacturing battery plate grids comprises starting with a strip of material from which the grid is to be formed, the strip having thickened side portions and a plurality of longitudinal ribs parallel with the side portions. The strip is passed between rollers which contain an impression of the required grid, and material is caused to flow by the rollers from the thickened side portions and the ribs to enhance the formation of the peripheral frame of the grid.

This invention relates to a method of manufacturing battery plate grids.

It has been proposed to manufacture a battery plate grid having a generally rectangular peripheral frame and a network of longitudinally and transversely extending ribs by rolling a strip of material (for example lead) between rollers which contain an impression of the required grid. However, it is difficult to perform this process satisfactorily because the grid material does not flow sufficiently to fill in the peripheral frame. It has also been proposed, with a view to overcoming this problem, to manufacture grids having diagonally extending ribs. In manufacturing such grids, the depressions in the roller corresponding to the diagonal ribs aid the flow of material during rolling so that more satisfactory filling of the frame results. However, even this improvement is found to be unsatisfactory for large scale production and the present invention seeks to provide an improved method of manufacturing a grid.

A method according to the invention comprises starting with a strip of material from which the grid is to be formed, the strip having thickened side portions and a plurality of longitudinal ribs parallel with the side portions, and passing the strip between rollers which contain an impression of the required grid, material being caused to flow by the rolling operation from the thickened side portions and the longitudinal ribs of the strip to enhance the formation of the peripheral frame of the grid.

The fiow of material is further improved if the ribs are diagonal, but the thickened side portions and longitudinal ribs are also of considerable assistance in manufacturing grids with longitudinal and transverse ribs.

One example of the invention is illustrated in the accompanying drawings wherein:

FIG. 1 is a diagrammatic plan view of a battery plate grid and,

FIG. 2 is a sectional view of a strip of material from which the grid shown in FIG. 1 is manufacutred.

Referring first to FIG. 1 the grid 11 to be manufactured comprises a rectangular frame 12 having its upper and lower sides interconnected by four parallel ribs 13 of diamond shaped cross section, the ribs 13 being of thickness equal to the thickness of the sides of the frame 12. The sides of the frame 12 and the ribs 13 are ice interconnected by two sets of ribs 14, 15 which are oppositely inclined to the ribs 13. The ribs 14, 15 are triangular in section the apices of the ribs 14 being co-planar with the front face of the frame 12 while the apices of the ribs 15 are co-planar with the rear face of the frame 12. The bases of the ribs 14, 15 all lie in a plane mid-way between the front and rear faces of the frame. The upper side of the frame 12 has integral therewith a connecting lug 12a.

In order to manufacture the grid 11 a strip 16 of dispersion strengthened lead having thickened edge portions 17, 18 and four ribs 19 parallel with the portions 17, 18 is passed between a pair of rollers. The rollers both have depressions therein corresponding to the sides of the frame 12 and the ribs 13 of the grid and one of the rollers also has helically extending depressions therein corresponding with the ribs 14 while the other roller has helically extending depressions therein corresponding to the ribs 15.

During the rolling operation the portions 17, 18 and the ribs 19 of the strip 16 engage the recesses in the rollers corresponding with the vertical sides of frame 12 and the ribs 13 of the grid respectively and the rolling operation causes lead to flow from the areas of the sheet between the portions 17, 18 and the ribs 19 and from the ribs 19 and the portions 17, 18 themselves into the recesses in the rollers corresponding with the ribs 14, 15 and the upper and lower sides of the frame, of the grid. The inclination of the recesses corresponding with the ribs 14, 15 aids the lateral flow of lead into recesses in the rollers constituting the upper and lower sides of frame 12 and the lug 12a.

Ideally the rolling operation should leave the areas between the ribs of the grid open, but in practice this desideratum is almost impossible to achieve and thin fillets of lead are left between the ribs. These fillets of lead are removed by a subsequent stamping operation.

This invention is not limited to lead grids and could, for example, be used to manufacture plastic grids from sheeting. A suitable material for this purpose would be polypropylene with about 40% talc by weight.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A method of manufacturing battery plate grids, comprising starting with a strip of material from which the grid is to be formed, the strip having thickened side portions and a plurality of longitudinal ribs parallel with the side portions, and passing the strip between rollers which contain an impression of the required grid, material being caused to flow laterally by the rolling operation from the thickened side portions and the longitudinal ribs of the strip to enhance the formation of the peripheral frame of the grid.

2. A method as claimed in claim 1 in which the grid has ribs which extend diagonally.

3. A method as claimed in claim 1 in which the grid has ribs which extend longitudinally and transversely.

References Cited UNITED STATES PATENTS 5/1909 Williams 72187 7/1925 Holland et a1. 292

LOWELL A. LARSON, Primary Examiner 

